The impact of changing residential programs on the lives of severely-profoundly retarded adults will be studied prospectively for 2 1/2 years. The major goal is to identify important social and non-social variables that influence the ongoing behavior of this population. The significance of this study relates to designing more optimal residential programs based on scientific data about basic environment-behavior relationships. The primary methodology is directed behavior observations of residents in both living and training settings. Supplemental data include standardized assessment of skill levels, data about staff and family attitudes, physical health, and detailed description of the residential environments. Baseline data will be collected for six months on individuals currently residing in a traditional institution--a large, isolated facility with 30-50 bed wards, and limited staffing and programming. After baseline, samples of residents will be assigned on a random stratified basis either to move to new living units or to stay in the old wards. Follow-up data will be collected for 12 months. The variables hypothesized to be critical determinants of behavioral change include: (1) size and composition of social groups, (2) amount of individualtized training, (3) opportunity to interact with others, (4) diversity of program resources, (5) prior history of individuals, and (6) biological factors.